CLINICIAN'S CAPSULE What is known about the topic? Current diagnostic tools for heart failure in the emergency department (ED) have limited accuracy and often lead to delays in management. What did this study ask? What is the accuracy of early bedside lung ultrasound in the diagnosis of acute decompensated heart failure? What did this study find? This meta-analysis found that the sensitivity and specificity of bedside lung US in ADHF is 82.5% and 83.6%, respectively. Why does this study matter to clinicians? The implementation of early bedside lung US in the ED may lead to more accurate and timely diagnoses of ADHF.

Introduction: Dyspnea is a common presenting problem in the emergency department (ED) that frequently creates a diagnostic challenge for physicians. Acute decompensated heart failure (ADHF) represents a common cause that requires prompt diagnosis and management. Recent studies on dyspneic patients have suggested a potential role for point-of-care ultrasound (PoCUS). The objective of this systematic review was to assess the sensitivity and specificity of early bedside lung ultrasound in patients presenting to the ED with dyspnea. Methods: A search of the literature was conducted using PubMed, EMBASE, the Cochrane Library, bibliographies of previous systematic reviews, and abstracts from major emergency medicine conferences. We included prospective studies that assessed the diagnostic accuracy of B-lines from bedside lung ultrasound in the ED patients compared to a clinical diagnosis of ADHF at hospital discharge. The final diagnosis included at least one of CXR, computed tomography, or BNP. Two reviewers independently screened all titles and abstracts for possible inclusions. Two separate content experts full text-reviewed selected studies and performed quality analysis using a modified Critical Appraisal Skills Program (CASP) questionnaire. Extracted data was assessed with summary receiver operator characteristics curve (SROC) analysis with pooled sensitivity and specificity. Heterogenity was tested. Results: The electronic search yielded 3674 articles of which six met the inclusion criteria and fulfilled CASP requirements for methodological quality. The total number of patients in these studies was 1911. Heterogeneity was noted; due to poorer performance by novice users. Meta-analysis of the data showed that in detecting ADHF, bedside lung ultrasound had a pooled sensitivity of 89.6% (95% CI 69.5 to 97.0%) and a pooled specificity of 88.4% (95% CI 75.0 to 95.1%). The positive likelihood ratio was 6.01 (95% CI 2.93 to 12.32) and negative likelihood ratio was 0.13 (95% CI 0.06 to 0.30). Conclusion: This study suggests that in patients presenting to the ED with undifferentiated dyspnea, early point of care lung ultrasound may be used to confirm the diagnosis of ADHF, which may facilitate earlier appropriate management. Test performance may vary according to experience.